Field of the Invention
The present invention is related to a device for fastening a heat sink to a heat-generating device, and particularly to a clip for fastening a heat sink to a central processing unit (hereafter, "CPU") mounted on a Zero-Insertion-Force connector (hereafter, "ZIF connector").
As the consuming power of a CPU becomes greater and greater, the CPU gets hotter and hotter. Should the heat not be dissipated timely and properly, a malfunction or unreliability of the CPU will happen. To overcome this problem, a heat sink made of aluminum stock is used to contact with the CPU whereby heat can be absorbed by the heat sink and dissipated to the surrounding environment. The heat sink is tightly contacted with the CPU mounted on a ZIF connector by a fastening device, wherein the fastening device is in the form of a clip having a first end engaging with a first lug on the connector, an opposite second end engaging with a second lug on the connector and an elongate body portion between the first and second ends pressing the heat sink against the CPU.
FIG. 1 is a drawing copied from U.S. Pat. No. 5,671,118 illustrating a conventional clip 50 for fastening a heat sink 12 to a CPU 10 mounted on a ZIF connector 4. The connector 4 is usually soldered to a mother board (not shown). The clip 50 has a first end 502 engaging with a first lug 42 of the connector 4, an opposite second end 504 engaging with a second lug 44 of the connector 4 and an elongate body portion 56 between the ends 502, 504 pressing the heat sink 12 toward the CPU 10 to has the heat sink 12 intimately contacted with the CPU. A finger manipulating portion 508 is formed by the clip 50 at a top of the second end 504 whereby a user can directly use his (her) fingers to achieve/release the engagement between second end 504 of the clip 50 and the second lug 44. Thus, the heat sink 12 can be mounted to/dismounted from the CPU 10 for the purpose of replacement or maintenance.
Since the layout of some mother boards has electronic components (such as capacitors) located around the finger operating portion 508, which causes the access of the user's fingers to this portion to be difficult or even impossible, resulting in an operational difficulty in achieving/releasing the engagement between the second end 504 of the clip 50 and the second lug 44 of the connector 4.
FIG. 2 is a drawing copied from Taiwan Patent Application No. 83218065, disclosing a clip 5 for achieving the same function as the clip 50 of U.S. Pat. No. 5,671,118. The clip 5 has a first end 53 defining a lower hole 54, an upper hole 56 and a rib 57 between the two holes 54, 56. A second end 53' defines a lower hole 54', an upper hole 56' and a rib 57' between the two holes 54', 56'. The clip 5 further has an elongate body portion 51 between the two ends 53, 53' for pressing the heat sink toward the CPU. The lower holes 54, 54' are used for fitting with the lugs of the connector. To release the engagement between the clip 5 and the connector, a tip of a tool, for example, a flat screwdriver, is extended through one of the upper holes 56 (56') to abut against a corresponding rib 57 (57'). Then, a force is exerted to the rib 57 (57') by the screwdriver to cause the corresponding end 53 (53') to deflect away from the corresponding lug, whereby the engagement between the corresponding lower hole 54 (54') and the lug is released. Thus, the heat sink and the CPU can be detached from the connector for replacement or maintenance.
To use a tool is not so convenient than directly use the fingers. However, in some circumstances, the use of a tool to manipulate the clip is unavoidable.
Hence, an improved clip is needed to eliminate the above mentioned defects of current clips.